Video Transcoding

If you're building applications with streaming capabilities, you require strong streaming APIs and SDKs to guarantee smooth delivery across different devices and platforms. Prioritizing streaming APIs equipped with video transcoding capabilities could mean better user experience, efficient bandwidth usage, and scalability.

What Is Video Transcoding?

Transcoding is the process of changing the format of video files. It involves changing the bitrate, codec, resolution, or container format to ensure compatibility with different platforms, devices, or internet connection speeds.

Video transcoding optimizes video content on different devices without compromising quality or compatibility. It also enables streaming media files over the Internet and compresses video and audio files to reduce storage space.

The encoding process is a little different from transmuxing or rewrapping. When a digital camera records video tracks, it can either compress the video right away or send it to a linked encoder to be compressed.

However, the process of transmuxing or rewrapping involves repackaging compressed content into a different delivery format without changing aspects such as the codec. For example, with transmuxing, you can change a WebM video file to an MP4 file.

Ideally, this process often involves two processes: transrating and transsizing.

Transrating changes the bitrate of a video stream without changing the format, codec, or resolution of the video. Transrating allows users to stream at lower bitrates by reducing the size of the video stream to accommodate lower bandwidth connections.

On the other hand, transsizing involves optimizing the video for different devices or screen sizes. You change the resolution of a video track without changing the bitrate or format of the video.

How Does Video Transcoding Work?

This process often involves taking your video or audio files, decoding them into an uncompressed intermediate format, and then re-encoding them into their final format. The process is likely to also include transrating, transsizing, and image scaling.

Video files are made up of four elements, including:

• The container or wrapper: It includes audio, video, and metadata in a single file and facilitates playback by checking for compatibility and synchronization across streams. Examples include .MP4, .MOV, .AVI, etc.

• The video codec: Examples include H.264, H.265/HEVC, AV1, VP9, and MPEG-4.

• The audio codec: Examples include MP3, AC-3, AAC, and Opus.

• Additional metadata: Includes additional information that provides context and details about the video file. This could be technical metadata that gives information about bitrates, resolutions, codecs, or frame rates. It could also be descriptive metadata that includes information on the author, title, or creation date.

Some of the most common tools used for video transcoding include:

• FFmpeg

• HandBrake

• Adobe Media Encoder

You first begin with importing raw video files from storage devices or cameras. This is followed by converting the footage to an intermediate codec for easy editing.

The next step is to edit the video and transcode it into different formats and resolutions for different platforms. Once you're done, you can archive the files in the right format and distribute them to the right platforms.

What Are the Common Use Cases for Video Transcoding?

Videos are transcoded to improve compatibility and performance.

Here are some other common use cases.

Streaming

During streaming, you can produce multiple versions of the same video at various bitrates and resolutions. Depending on the viewer's device and internet speed, the streaming service can dynamically switch between these versions.

For instance, to make their video tracks work on more devices and in more network settings, streaming services like YouTube, Amazon Prime Video, and Netflix leverage transcoding.

It aids in optimizing bandwidth usage so that users with slow internet connections can still access lower-resolution and bitrate streams.

Post-Production Workflows

In post-production processes, video transcoding is essential for transforming video files into formats that are editable, distributable, and archivable.

Some camera raw footage formats are incompatible with video editing software. As such, you get to transform these files into editing-optimal formats like CineForm, DNxHD, or ProRes.

You can also generate proxy files with a reduced resolution. Due to their small size, these proxies make editing much easier, particularly on computers with lower processing power. When you're ready to export, you can use the original, high-resolution files.

It also makes it easier to store and manage massive amounts of video tracks by reducing file sizes without drastically sacrificing quality.

Video Compression

Smaller file sizes require less bandwidth to stream and download videos, which is critical for both content providers and users on limited data plans. As such, it is necessary to compress video tracks into file formats that are compatible with different devices.

Creating multiple compressed versions of a video also allows for adaptive streaming, which adjusts the video quality in real time, ensuring uninterrupted playback without buffering.

Network Transfers

Transcoding supports protocols such as HTTP Live Streaming (HLS), Smooth Streaming, and Dynamic Adaptive Streaming over HTTP (DASH), which improve video delivery over the internet. These protocols modify the quality of videos streamed in response to network conditions through adaptive bitrate streaming.

For instance, you can stream a 4K movie encoded with HEVC/H.265 in MKV format from your Media Server to a TV that only supports H.264 in MP4.

Adding Subtitles or Captions to Videos

Modern media players and streaming services make it easy to toggle between subtitle tracks. This is because you can integrate subtitles in multiple formats.

For display flexibility and playback system compatibility, closed captions are typically either added as a separate track or embedded in the video file's metadata. In fact, advanced video playback solutions use speech-to-text technology to automatically generate subtitles.

Why Is Video Transcoding Important?

Video transcoding comes with several benefits.

Here are some of them. 

Ensures Compatibility

Transcoding ensures videos work on all sorts of devices, such as smart TVs, tablets, mobile devices, and video streaming players.

Video playback is frequently subject to device-specific specifications. By adjusting the codec, bitrate, and resolution, you can make videos accessible on different devices.

Optimizes Streaming

To ensure smooth playback on a variety of user platforms and bandwidths, Over-the-top (OTT) video streaming services have to transcode videos into multiple formats and resolutions.

Some users, especially those with slow internet connections, may have issues viewing high-resolution videos with high bitrates. For flawless playback, you can make lower-resolution, lower-bitrate copies of the original video.

For instance, Zoom is able to transcode video streams so that participants with varying internet speeds and devices can join in without any problems.

Enhances Video Optimization Processes

By creating numerous versions of a video with different bitrates, your video player can dynamically switch between quality levels depending on the viewer's internet speed. This feature greatly enhances playback quality and eliminates buffering.

You can improve video optimization by:

• Adjusting resolution and aspect ratios

• Ensuring format compatibility

• Managing bitrate and video size

• Enabling adaptive bitrate streaming

• Increasing compression efficiency

Improves Accessibility

Transcoding video content makes it playable on a wide range of assistive devices, like voice control systems and braille displays, thus improving accessibility.

Additionally, it allows for the addition of closed captions and subtitles, which help users with hearing impairments understand the video content.

With the proper metadata, screen readers can display captions, increasing accessibility for visually impaired users.

Helps in File Size Reduction

Many video files include metadata, additional audio tracks, or subtitles that aren't needed. By removing this extraneous data, you end up reducing the overall file size for each video.

You can minimize the total video size by changing the bitrate or video resolution.

Changing a video's resolution from 4K to 1080p or 720p, for example, can make the video size a lot smaller. This comes in handy especially if the intended player doesn't have high resolution requirements.

Best Practices for Video Transcoding

It's essential to keep the following tips and tricks in mind to maximize the quality of your video streams and delivery.

Use Adaptive Bitrate Streaming (ABR)

Adaptive bitrate streaming automatically changes the stream quality based on the user's current bandwidth. Video is encoded at multiple bitrates and then switched in real time to users.

By efficiently using available bandwidth without overloading it, ABR streams at the highest possible quality your viewer's network can handle.

With ABR, the video player can automatically adjust the quality level to the user's network conditions, eliminating buffering and guaranteeing uninterrupted playback.

Use Two-Pass Variable Bitrate (VBR) Encoding

In the initial pass, the encoder records information about scene changes, motion, and complexity from the whole video. With the information gathered, in the second pass the encoder is able to allocate bitrates more effectively.

Compared to single-pass encoding, two-pass VBR encoding typically results in smaller file sizes. Two-pass VBR also produces a more balanced and aesthetically pleasing output by optimizing the bitrate based on scene complexity.

Use a Cloud Transcoding Service

These services let you scale up or down your computational resources on demand. This comes in handy when there are sudden increases in the demand for video processing.

Furthermore, you can convert numerous video files at once, drastically reducing the time needed for massive projects.

Additionally, cloud services frequently incorporate cutting-edge codecs and technology, giving you access to advanced features like AI-driven optimizations and compatibility with new video formats.

What's more, these services provide APIs and SDKs that simplify adding video optimization features to existing workflows, apps, or content management systems.

Some of the most common cloud-based services include AWS Elemental MediaConvert and Google Cloud Transcoder.

Know Which Bitrate to Use

Choosing the correct bitrate is crucial for streaming applications to avoid buffering issues. It improves the viewing experience for users with different internet speeds by efficiently using available bandwidth.

You can implement ABR to find the right bitrates for various quality levels. With ABR, content automatically adjusts to the viewer's network and device specifications.

Leverage Artificial Intelligence (AI)

AI can analyze video content to comprehend its visual details, motion, and complexity, thus enabling intelligent bitrate allocation. With AI-assisted transcoding, scenes with more complexity get higher bitrates, and scenes with less complexity use lower bitrates to save bandwidth and file size.

AI algorithms can adaptively choose the optimal encoding settings for each segment of the video to optimize compression without sacrificing quality.

AI can improve ABR by monitoring user actions and network conditions to fine-tune streaming quality, resulting in a seamless viewing experience.

Enhance Your Overall Streaming Experience

Businesses can guarantee efficient delivery of high-quality video content across different devices and network conditions by leveraging video transcoding.

One way to do this is to integrate third-party APIs when developing video chat features for your applications. APIs let you customize your video chat and live streaming solutions to meet your business's needs.

What's more, APIs allow you to test different streaming features and technologies without the hassle of building the solution from scratch. When picking an API to extend, make sure it comes with video optimization features so you can deliver the best quality to your user base.

Frequently Asked Questions